1. Field of the Invention
The present invention relates to portable earth anchors and foundation piers. In particular, the present invention is directed to a transportable guy wire anchor for logging cable yarders.
2. Description of the Prior Art
Cable logging is a technique frequently used for removing felled trees from rough, mountainous terrain whereby a skyline cable is drawn over a sheave block near the top of a yarder mast and out from the mast over a cutting area. The distal end of the skyline is secured to the ground at a point remote from the yarder; occasionally after passing over a tail block secured to the top of second, remote end mast.
The primary skyline cable carries a sheave mounted carriage block from which a load line is dropped for picking up the load.
In this system, the yarder is a portable, usually truck mounted, power unit associated with a mast structure for driving and controlling several cable winches necessary for reeling and tensioning the skyline, load and carriage traverse cables.
Obviously, all vertical loads on a cable system are supported compressively by the mast. However, the mast, being truck mounted, has relatively little moment restraint against lateral loads. For this reason, the mast is secured laterally by guy wires tensioned from the mast a ground anchor.
As a logging operation progresses, it is necessary to frequently realign or move the cable system. Even if the yarder and mast are not physically transposed, the skyline tail will be aligned along a different azimuth to service a different radial segment of terrain from the yarder center. Such change in azimuth alignment will also require a repositionment of anchor points for the guy wires and dead lines from the mast sheave blocks.
If possible, cable system riggers seek out a large tree or stump for ground anchorage of guy wires and dead lines. However, considering the number of anchor points required for a system against the allowable cone of discretion for each, a suitable tree stump is not always available. In the absence of a suitable anchor tree or stump, the prior art practice is to secure the anchor line around a sizable log for burial at approximately six feet. Although excavating equipment such as backhoes and crawler/scrapers are normally present at logging sites for such tasks, bed rock and massive boulders underlying thin, mountainous topsoil greatly complicate the excavation task.
Collectively, therefore, appropriate anchorage of a cable system represents one of the more perplexing and frequently recurring problems in the cable riggers art and to which the present invention is addressed.
Accordingly, it is an object of the present invention to teach a method of anchoring cable systems that is as portable as the yarder and applicable to most types of forested mountain terrain.
Another object of the present invention is provision of a transportable anchor pier having sufficient mass and ground adherence to secure cable logging guy wires and dead lines.
Another object of the present invention is provision of a multiple purpose pier for logging operations that may be used for small stream and gully bridge foundations and for anchoring skyline cable log retrieving systems.